What term means that a mineral cannot form from materials that were once part of a living thing?

After examining the evidence at a site, a geologist thinks that a river could have once flowed through the area. what evidence would support this conclusion? a) the site is a vast, open grassland. b) a high level of tectonic activity is present. c) this location contains igneous rocks everywhere. d) many sedimentary rocks with fossils have been found.